Re: help please-hard question

Suposse that your given ordered pairs belong to the cartesian product that defines a function. Then they will be in the form . Now recall the definition of a function, in particular about the uniqueness about

Re: help please-hard question

not to worry sorry i figured out that because it has the same -1 on both plots it is not a function.

what about this one-
The points (1, 3) and (2, 3) satisfy a relation R, which of the following can we (definitely) conclude?

Select one:
a. R is a function
b. R is not a function
c. R is y=3
d. R is a straight line
e. None of the above

I know its a straight line and is function but neither answers are right? what would be the right answer?

No, you don't know either of those things. For example the relation containing pairs {(1, 3), (2, 3), (1, -3)} and y= x for x not equal to 1 or 2 is not a function nor a straight line but sastisfies the conditions. You seem to be under the impression that since we have both (1, 3) and (2, 3) we must have "y= 3" for all x. That is possible but not necessary.

Re: help please-hard question

Originally Posted by emakarov

As HallsofIvy describes, in this case the trend is misleading. It does not follow that R has properties (a)-(d).

I don't understand. We have the points (1,3) and (2,3) and we are to conclude a relation between these points. y=3 in both points so how come this does not satisfy a 'relationship' between these two points? Nobody said anything about all x. Or maybe I am misunderstanding?

Re: help please-hard question

Originally Posted by Paze

We have the points (1,3) and (2,3) and we are to conclude a relation between these points. y=3 in both points so how come this does not satisfy a 'relationship' between these two points? Nobody said anything about all x. Or maybe I am misunderstanding?

Yes, the question is about all x. That is, the question is about R as a whole, about all pairs (x, y) in R. And it asks not what type of R could contain (1, 3) and (2, 3), but what statements about R follow with necessity. Neither of statements (a)-(d) do.